The phrase 'fervent voice' is correct and can be used in written English.
You could use it to describe someone who is speaking passionately and with a lot of energy and emotion. For example: "The speaker's fervent voice filled the room as they passionately argued their point."
Phalanxes of backup choirs flank Ms. Welch's own fervent voice.
In the last year, Ms. Sandrow has been a fervent voice for preserving the house.
His trademarks were a bushy beard and his fervent voice, somewhere between a snarl and a yelp.
Whether he's singing an Afrocentric love song or screaming for revenge against "Babylon," his fervent voice turns every lyric into a life-or-death struggle.
More broadly, Germany has been the most fervent voice that reckless economic pursuits should be punished, no matter the human toll.
Jurgis falls in with criminals and corrupt politicians, and then, suddenly, at a public meeting, he's electrified by a fervent voice: "They own not merely the labor of society, they have bought the governments; and everywhere they use their raped and stolen power to intrench themselves in their privileges".
They sang unaccompanied in the classic quartet style, with fervent voices growling and leaping out of rhythmic chords.
The tenor Francesco Meli was in fervent, ringing voice as Gabriele, and the strong bass Dmitry Belosselskiy was aptly forbidding as Fiesco.
He had a high, fervent tenor voice, and the songs and arrangements he wrote were driven by supercharged horns and percussion.
The Police have their old strengths: Sting's springy bass lines and his reedy, fervent, undiminished voice; Stewart Copeland's drumming, with its mixture of thwacking propulsion and flurries of jazzy detail; Andy Summers's resourceful guitar parts, creating the harmonies with watercolor transparency.
Fervent solo voices are answered with comforting chorales; dynamics are precise, even without a conductor.
